"When I spoke about the Classical Audio Café I did not mean that a dally eatery but rather a recursive sequences of audio performing events in a given installation."
I really like the Classical Audio Café concept. Especially if it were open only occasionally, with top-tier "performances," and matching themes, such as food (great idea), perhaps without going overboard, some relevant artwork and a brief historic presentation which could be in the form of a handout or brief interjections from a passionate historian.
Opening a stand-alone business every day would be a non-starter in the US from an economic standpoint (might work in Manhattan if you could find a large space free of charge). Regardless, daily "performances" would become a bit more mechanized, less special than occasional ones.
More importantly, the Classical Audio Café could have a great cultural impact if we step out of the capitalistic framework. How about linking up the concept with a university or several universities. If you pitch the idea correctly there is some reasonable space available for free at universities and students willing to volunteer or work at a reasonable fee. Here in Boston, the Berkeley School of Music, Harvard and Northeastern come to mind, each for different reasons. The abandoned WGBH building Harvard recently purchased could house several cafes simultaneously...
Challenges would include promotion and logistics (lugging equipment around); as always, there is an abundance of students looking for these types of excuses to stay away from the library. University catering teams could help with the food and beverages, and the university would keep any profits (I mean losses!).
Getting reasonable sound would be an entirely different beast, however...